Air conditioning system



June 5, 1956 M. PARCARO 2,743,572

AIR CONDITIONING SYSTEM Filed Dec. 6, 1952 INVENTOR I Michael Pa i'com'o 2,748,572 Patented June 5, 1956 AIR CONDITIONING SYSTEM Michael Parcaro, Arlington, N. J.

Application December 6, 1952, Serial No. 324,558

3 Claims. (Cl. 62-4) This invention relates to air conditioning, and more in particular, to a system for selectively heating or cooling air passing to or within a conditioned space so as to control automatically the temperature during the cool or winter periods, and also during the warm or summer periods.

An object of this invention is to provide a fully automatic air conditioning system which overcomes many practical difiiculties which have been encountered in the past with other systems. A further object is to provide such a system where the operation is carried on automatically with full assurance that no harm will result from improper manipulation of the controls and other circumstances which might be created.

A further object is to provide an air conditioning system utilizing a medium, such as well water, as a source of heat during the periods of winter operation and also as a heat-absorbing medium during the periods of summer operation, and wherein the inadequacy or total failure of supply of the well water or other medium will result in discontinuing the air conditioning operation. A further object is to provide for all of the above in such a manner as to insure efiicient and dependable operation. These and other objects will be in part obvious and in part pointed out below.

In the drawings the single figure is a schematic representation of an illustrative embodiment of the invention.

Referring to the drawing, an air conditioning system is represented having: a compressor 2 driven by a motor 3; an evaporator-condenser unit 4; a receiver 6; and, a condenser-evaporator unit 8. Compressor 2 has an inlet it and an outlet 12 which are connected to a refrigerant flow-reversing valve 14-. Units 4 and 8 act respectively as the evaporator and the condenser of the system during summer operation, and respectively as the condenser and the evaporator during winter operation. Evaporator-condenser unit 4 is connected to valve 14 through a pipe 16, and condenser-evaporator unit 8 is connected to the valve through a pipe 18. Receiver 6 is connected through a pipe 20 and an expansion valve 22 to the top of the evaporator-condenser unit 4; and, pipe 26 has an expansion valve 22 therein with its bulb in contact with pipe 16.

There is a reverse-flow by-pass pipe 24 which connects pipe 20 to the bottom of the evaporator-condenser unit 4-, and which has a one-way valve 26 therein so that there is free flow from unit 4 to the receiver, but not in reverse. Thus, when unit 4 is acting as a condenser, the liquid refrigerant flows downwardly from the bottom of the unit to the receiver, but when unit 4 is acting as an evaporator, the upward flow from the receiver must be through the expansion valve 22. Receiver 6 is also connected in a somewhat similar manner to the condenserevaporator 8 by a pipe 28 with an expansion valve 30 therein through which the liquid refrigerant must flow from the receiver during winter operation, and a bypass pipe 32 with a one-way valve 34 therein through which the liquid refrigerant flows to the receiver during winter operation.

The air being conditioned is directed over the evaporator-condenser unit 4 by a fan 36 driven by a motor 38, and the temperature of the conditioned air within the conditioned space is sensed by a heating or winter thermostat 4t) and also by a cooling or summer thermostat 42. The condenser-evaporator unit 8 is enclosed within a water shell or tank 44 through which there is constant circulation of water during both summer and winter operations. The water is supplied by a pump 46 from a well, and flows from the tank through a restricted outlet 48. Pump 46 is driven by a motor 50 which is started automatically whenever there is-a demand for either heating or cooling.

Connected to tank 44 by a pipe 52 is a switch-operating pressure unit 54 which closes an electric switch 56 when the pressure within the tank 44 is raised by the pumping of water into the tank. As will be explained more fully below, switch 56 is a master control switch, which is open whenever water is not being supplied to tank 44, but which closes whenever there is a satisfactory supply of water. The opening of this master control switch prevents the operation of the refrigeration system and therefore, the refrigeration system cannot be operated when there is not a satisfactory supply of water to cool or heat the condenser-evaporator unit 8. The motor compressor has a high and low cut-off switch unit 58 which stops the compressor motor 3 whenever the pressure of the compressed gas exceeds a predetermined high value, or when the suction pressure at the intake of the compressor falls below a predetermined value.

It has been indicated above that there is a flow-reversing valve 14, which is represented somewhat schematically, but which is constructed to give the refrigerant flow paths as referred to above and as will now be described in detail. Valve 14 has a reversing valve mechanism represented in the form of a lever 60 pivoted at 61 and carrying at the right a double-seat valve member 62, and at the left a similar valve member 64. When the lever 60 is in the normal rest position shown, valve member 62 has its top valve seat closing a port above it to a passageway 68; and, a port below the valve member is open thus connecting pipe 12 to a passageway '70. This causes the compressed gas from the compressor to flow through pipe 18 to the condenser-evaporator unit 8.

Valve member 64 is at this time positioned so as to close its lower port to passageway 70 and to open its upper port to passageway 68; and, this connects the intake pipe from the suction side of the compressor through passageway 68 and pipe 16 to the evaporator-condenser unit 4. Thus, when the compressor is in operation, refrigerant is withdrawn from unit 4, thereby causing this unit to operate as an evaporator and to cool the air blown over it by fan 36. The compressed refrigerant then flows to unit 8 which acts as a condenser so that the refrigerant condenses, and the liquid refrigerant flows through the one-way valve 34 and pipe 32 to receiver 6. The liquid refrigerant then flows from receiver 6 through pipe 2b and expansion valve 22 to unit 4 thus completing the refrigerant ilow path during the cooling cycle. As indicated above, the expansion valve 22 is controlled automatically by its bulb, thus to maintain the desired operating conditions.

During the heating cycle, the reversing valve lever 61) is rocked clockwise by the energization of a solenoid 72. This moves valve member 64 up to close its top port and open its bottom port and moves valve member 62 down to close its bottom port and open its top port. This connects the refrigerant inlet pipe 10 through passageway 70 and pipe 18 to unit 8, and connects the refrigerant outlet pipe 12 through passageway 68 and pipe 36 to unit 4. Thus, the compressed refrigerant flows from the compressor through pipe 12, passageway 68 and pipe 16 to unit 4, and it heats the air which is blown over it by fan 36. The refrigerant condenses and in liquid form flows through one-way valve 26 and pipes 24 and to receiver 6.

The intake or low side of the compressor now is connected through pipe 10, passageway 70 and pipe 18 to unit 8, thus to cause unit 8 to act as an evaporator. Liquid refrigerant flows to unit 8 through pipe 28 and expansion valve 30 which has its control bulb on pipe 18. The refrigerant evaporating in unit 8 withdraws heat from the surrounding water which is being pumped through tank 44. Thus, the system withdraws heat from the water and delivers it to the air and operates as a heat pump or reverse cycle unit.

The electrical control systems includes: the heating or winter" thermostat and the cooling or summer thermostat 42, referred to above; a compressor motor relay 74; a manual double-throw switch 76 which is swung to the right for automatic operation of the system and to the left for the operation of the fan alone when no heating or cooling is desired; a heating relay 78 which is energized by the closing of the heating thermostat 49; a pump motor relay 80 which is energized to start the pump; and, the master control pressure switch 56 referred to above.

This control system gives fully automatic operation when either heating or cooling is required, with the heating thermostat 40 controlling the heating operation and with the cooling thermostat 42 controlling the cooling operation. However, switch 76 may be operated to render the heating and cooling operations inoperative by throwing this switch from the right-hand automatic position to the left-hand fan position wherein the fan 36 operates continuously. As indicated above, the reversing valve 14 is in the position shown during the cooling operation, and it is reversed during the heating operation by the energization of solenoid 72. The compressor motor relay 74 has four normally open switches 71, 73, 75 and 77, which are all closed by the energization of solenoid 79 to supply power to the compressor motor 3. The heating relay 78 has two normally open switches which are closed by the energization of a solenoid 87,

there being a heating switch 81 and a pump switch 85.

Electrical power is supplied for the electric motors 3, 38 and 50 and for the control system by three power lines 84, S6 and 88. The pump motor relay has a pair of switches which are connected respectively to pump motor lines 94 and 86, and which are closed simultaneously by the energization of a solenoid 82 to connect line to a line 94 and connect line 92 to power line 86. Line )4 is connected to a terminal 98 of switch 76 which has its double armature 100 connected to power line 84 for automatic operation. With switch 76 set for automatic operation, its armature is swung to the right so as to connect line 84 to line 94, and the closing of relay 88 connects the pump motor across power lines 84 and 86. Also connected across lines 94 and 86 is the primary winding of a relay power transformer 102 which has its secondary winding connected to a series circuit formed by solenoid 82 of relay 8t) and the switch 96 of the cooling thermostat 42; and. the pump switch 85 of the heating relay 78 is connected in parallel with switch 96. Therefore. when the cooling thermostat switch 96 closes so as to call for cooling, or if switch 85 is closed so as to call for heating, solenoid 82 is energized and the switches of relay 80 are closed. As indicated above, this starts the pump motor 58 which is the first step toward operating the system.

Solenoid 87 of the heating relay 78 is connected to the secondary winding of a transformer 104, the primary winding of which has one side connected to line 86 and the other side connected to a right-hand terminal 106 of switch 76, and thence to line 84 when switch 76 is in the position for automatic operation. The circuit of solenoid 87 includes the switch 107 of heating relay 40 so that when switch 76 is positioned for automatic operation, the closing of the heating thermostat switch energizes solenoid 87 and closes the switches 81 and 85 of relay 78.

The compressor motor relay 74 has its solenoid 79 connected at one side to line 86, and the other side is con nected in series with the high and low cut-oil switch unit 58 and the water pressure switch 56 to line 94. It has been indicated above that line 94 is connected to line 34 when switch 76 is positioned for automatic operation. The high and low cut-off switch unit 58 has two switches which are normally closed, one of which opens when the compressor outlet pressure is excessively high, and the other of which opens when the suction is excessively low. The water pressure switch 56 is normally open and is closed only when pump 46 is operating and has supplied suflicient water to the tank 44 to raise the pressure therein to a predetermined value. Therefore, with switch 76 positioned for automatic operation, the circuit of solenoid 79 is normally conditioned to energize this solenoid whenever the pump 46 is started.

It has been indicated above that pump 46 is started by a demand for either cooling or heating, and either of such demands may be effective to close the switches of relay 80 and start the pump motor. In this way the initial effect of a demand for either heating or cooling is to start the pump motor so as to supply water to tank 44. The supplying of water to this tank then raises the pressure and closes switch 56, and this closes the electric circuit outlined above and energizes solenoid 79, and this closes the switches of the compressor motor relay 74. The closing of these switches 73, 75 and 77 starts the compressor motors and operates compressor 2.

The paths of refrigerant flow for the heating and cooling cycles have been outlined above. However, it should be noted here that the flow-reversing valve 14 is positioned as shown for the summer" or air-cooling opcration, and the fiow is reversed for the winter or heating operation. This flow reversal is effected by the energization of solenoid 72 which has one side connected to line 86 and the other side connected through switch 81 of the heating relay 78 and a line to terminal 106 of switch 76 which is at this time connected to line 84 in the manner outlined above. In this way, the closing of the heating relay 78 reverses the refrigerant flow,

Fan motor 38 has one side connected through a line 108 to line 86, and the other side is connected through a line 110 to switch 71 of relay 74, and the other side of switch 71 is connected to line 84. Therefore, the fan is operated whenever the compressor is operated for either heating or cooling. This same side of the fan motor is also connected through line 110 to the left-hand terminal 112 of switch 76, which terminal is connected to line 84 when this switch is positioned for fan operation. There fore, when switch 76 is positioned at the left for fan operation the fan motor is energized continuously so as to operate the fan and circulate air regardless of the temperature conditions. This permits the operation of the system for air circulation when neither heating nor cooling is desired. Line 110 is also connected to a manual switch 114, the other side of which is connected to line 84. Thus, the fan may be operated continuously by closing switch 114 even though switch 76 is set for automatic operation. Such. continuous fan operation may be desirable when the conditions are such as to require a small amount of cooling occasionally with continuous air circulation.

The operation of the system described above may be fully automatic so as to maintain predetermined conditions over a wide range of the heating or cooling loads. lllustratively, the heating thermostat 40 may be set within an operating range of 68 degrees to 72 degrees F., while the cooling thermostat 42 is set within an operating range of 74 degrees to 85 degrees F. With such settings, the system will cool or heat automatically in accordance with the demand, without the necessity for any resetting or manipulations. During most periods of operation where heating is desirable, it is important that the fan be stopped when the heating is discontinued. However, during periods of cooling operation, and also under some circumstances where heating is being carried on, it is important to provide for the continuous operation of the fan. However, by providing for the starting and stopping of the fan simultaneously with the starting and stopping of the compressor, the system will carry on a basic pattern of eflicient operation. The operator may then provide for the continuous fan operation when conditions make that desirable. Furthermore, the fan may be operated continuously without any heating or cooling.

From the standpoint of safety and efficiency of operation, it should be noted that the refrigeration system can not be operated when there is not a satisfactory supply of water. Hence, if the pump motor should fail, or if the pump should, for any reason, not deliver a satisfactory amount of water, the refrigerator system will not operate. Therefore, the system cannot become damaged because of being operated with insuificient water. The electrical control system is also important from the standpoint of insuring high efiiciency operation. The cooling thermostat 42 exerts the primary control, but control is taken from the cooling thermostat when there is a demand for heating. However, the utilization of a single pump control relay as the unit which is responsive to both thermostats insures efficient and dependable operation. This is particularly true when the starting of the pump initiates the starting of the refrigeration system. Where the operating ranges are as suggested in the example above, there will be no change directly from a cooling operation, or vice versa. However, even if such a change should take place, the system is adapted to continue to operate in a dependable and efficient manner.

It is thus seen that an air conditioning system and a mode of operation have been disclosed by which objects above set forth are accomplished.

I claim:

1. In an air conditioning system of the character described which includes a refrigeration system having a compressor and main motor therefor and a cooling or heating coil through which air is directed to subject the air to a desirable heat transfer operation and which includes a heat absorbing or dissipating unit through which a stream of water passes so as to provide a source of heat or so as to carry away heat as desired, a pump and driving motor to supply said stream of water, a reversing valve which has two positions in one of which a fluid flow is provided to cause said coil to act as a heating coil and in the other of which a fluid flow is provided to cause said coil to act as a cooling coil, a solenoid unit which is energized to operate said reversing valve, a heating thermostat which is adapted to close when there is a demand for heating and to open when said demand is satisfied, a cooling thermostat which is adapted to close when there is a demand for cooling and to open when the demand is satisfied, circuit means which is adapted to energize said solenoid unit upon the closing of one of said thermostats, a normally open relay switch in parallel with said cooling thermostat, solenoid means to close said relay switch when said heating thermostat closes, circuit means which energizes said motor for said pump upon the closing of said cooling thermostat or said relay switch, a circulating fan for circulating air over said cooling or heating coil, a fan motor for driving said fan, circuit means including a main motor relay having a plurality of switches and a solenoid which is energized to close said switches, said circuit means connecting said main motor to power lines upon the closing of said switches and simultaneously starting said fan motor, an auxiliary switch which is closed to operate said fan motor independently of said motor relay, and circuit means for said motor relay including a pressure switch which is closed by the pumping of water under pressure by said pump and safety switches in series therewith which are opened by improper operating conditions of said compressor.

2. The system as described in claim 1, wherein said reversing valve is normally positioned to cause said refrigeration system to operate to cool air and which is reversed by the energization of said solenoid unit to cause said refrigeration system to heat air.

3. A system as described in claim 2, wherein said cooling and heating coil and said absorbing and dissipating unit each include one fluid passageway which is free of valves for the flow of refrigerant to and from said reversing valve, a receiver, a pair of check valves connected from said receiver respectively to said coil and said heat absorbing and dissipating unit, and a pair of expansion valves connected respectively in parallel with said check valves.

References Cited in the file of this patent UNITED STATES PATENTS 686,874 Wolcott Nov. 19, 1901 833,325 Hiester Oct. 16, 1906 1,273,577 Carroll July 23, 1918 1,302,596 Schweinle May 6, 1919 2,441,885 Kemler et al. May 18, 1948 2,513,373 Sporn et a1 July 4, 1950 2,585,748 De Silvestro Feb. 12, 1952 

